Acoustical ceiling suspension fastening system



ACOUSTIGAL CEILING SUSPENSION FASTENING SYSTEM Filed May 1, 1961 M. L.LYDARD June 8, 1965 2 Sheets-Sheet 1 llill M. L. LYDARD 3,187,856

ACOUSTICAL CEILING SUSPENSION FASTENING SYSTEM June 8, 1965ZSheets-Sheet 2 Filed May 1, 1961 FIG. IO

United States Patent 3,187,856 ACOUSTICAL CEILING SUSPENSIGN FASTENINGSYSTEM Martin L. Lydard, Ellicott City, Md., assignor to EasternProducts Corporation, Baltimore, Md, a corporation Maryland Filed May 1,1961, Ser. No. 1%,794 8 (Ilaims. (Cl. 189-66) The present inventionrelates to ceiling constructions and more particularly to suspendedceiling constructions in which a metallic grid system is suspended fromprimary ceiling members and is used to support acoustical tiles andother ceiling panels.

In recent years it has been common in the construction of new buildingsand in the renovation of old build ings to employ suspended ceilings inwhich acoustical tiles or other types of ceiling panels are supported byflanged beams, usually made of steel or aluminum. In most such systemsthe flanged beams are arranged in a rectangular grid system with longparallel beams, called main runners, being joined at suitable intervalsby transverse parallel beams, called cross-Ts, In some systems thebottom flange of the metal beams forms a part of the visible ceilingsurface, while in others the metal beams are not visible after theceiling panels are installed.

In acoustical ceiling systems in which main runners and cross-Ts arearranged into a rectangular grid, it is important that the attachment ofthe cross-Ts to the main runners afford substantial stability andrigidity. It is also desirable that attachment of the cross-T's to themain runners be effected with as little labor as possible and preferablywithout the use of tools. It is also desirable that the cross-Ts bereadily removable although it is important that accidental disengagementof the cross-Ts from the main runners be prevented.

In accordance with the foregoing, it has been a principal object of theinvention to provide a novel and improved suspension fastening systemfor acoustical ceilings.

More particularly, it has been an object of the invention to provide afastening system in which the cross-Ts may be easily attached to themain runners and which, when so attached, afiord a grid system havingexcellent stability and rigidity characteristics.

Another object of the invention has been the provision of a fasteningsystem in which the cross-Ts may be installed and locked to the mainrunners without the use of tools.

Another object of the invention has been the provision of a fasteningsystem in which cross-Ts are readily removable but in which accidentaldisengagement of the cross-Ts from the main runners is avoided.

A further object of the invention has been the provision of a fasteningsystem in which the cross-Ts may all be identical.

Other and further objects, features. and advantages of the inventionwill appear more fully from the following description of the inventiontaken in connection with the appended drawings, in which:

FIG. 1 is a fragmentary perspective view of a suspended ceiling gridsystem embodying the invention;

FIG. 2 is a fragmentary side elevational view of a typical main runnerfor use in the system of the invention;

FIG. 3 is a sectional view taken along the line 3-3 of FIG. 2;

FIG. 4 is a side elevational view of a cross-T constructed in accordancewith the invention;

FIG. 5 is an end elevational view of the cross-T of FIG. 4;

FIG. 6 is a side elevational view of a hook latch embodying theinvention and adapted for attachment to one end of the cross-T of FIG.4;

FIG. 7 is a top plan view of the hook latch of FIG. 6;

FIG. 8 is an end elevational view of the hook latch of FIG. 6;

FIG. 9 is an elevational view, partly in cross section showing anassembled cross-T and hook latch in position to be locked to a mainrunner;

FIG. 10 is a view similar to FIG. 9 with the hook latch locked to themain runner; and

FIG. 11 is a perspective view, partly exploded, showing one cross-T andhook latch assembled to one side of a main runner and another cross-Tand hook latch positioned to be brought into engagement with the otherside of the main runner.

Referring now to the drawings, and more particularly to FIG. 1, the gridsystem may comprise a series of parallel main runners, as shown at 20,21 and 22 and a series of parallel cross-Ts disposed at right angles tothe main runners and spaced at regular intervals. Cross- Ts are shown at23, 24, 25, 26, 27, 28, 29 and 30. Typically, the main runners will besuspended from roof trusses or other primary members by wires or othermeans well known in the art. The main runners will usually be relativelylong, 12 feet being a typical length, and main runners will be splicedtogether end to end to span the ceiling space. The cross-Ts will usuallybe spaced along the main runners at regular intervals, e.g., 2 or 4feet, and, typically, will be 2 or 4 feet long, providing grid openingsof a size to accommodate the acoustical tiles or other panels to besupported on the main runner and cross-T flanges.

A main runner is illustrated in detail in FIGS. 2 and 3 and comprises anupstanding web 31 formed from vertical portions 32 and 33 joined at thetop by a rounded rib 34. The vertical portions 32 and 33 terminate,respectively, in horizontal ceiling panel supporting flanges 35 and 36.The main runner in cross section is essentially shaped as an inverted Tand may be rolled or otherwise formed from a single sheet of metal. Inthe case of aluminum, the main runner will preferably be extruded andthe web 31 will be formed of a single thickness of metal. A decorativeflange cover 37 caps flanges 35 and 36 to provide an attractiveunder-surface which is desirable in installations where theunder-surface of the main runner forms a visible part of the installedceiling.

At suitable axial intervals, the main runner web 3-1 is provided withvertically elongated cross-T attaching holes or routes," as shown at 38in FIG. 2. The axial spacing between adjacent cross-T attaching routesmay be selected as desired to accommodate various grid structures, but,typically, this axial spacing might be 12 inches center to center.

The route 38 is located generally in the lower half of web 31 and hasvertical side walls 39 and 40. The side wall 39 terminates in inclinedwalls 41 and 42, while the side wall 40 terminates in inclined walls 43and 44. The walls 41-4-4 might, for example, be inclined at an angle tothe vertical of 15. The walls 41-44 meet short hori zontal walls 45, 46,47 and 43, respectively. The walls and 47 are joined by a semicircularwall 49, while the walls 42 and 44 are joined by a semicircular wall 56.Typically, the overall vertical height of the rcute bs might be 0.515inch, while the spacing between Walls 39 and 40 might be inch. Thevertical height of each of the Walls 41-44 might be 0.060 inch. Surfaces46 and 48 might be vertically spaced from the upper surfaces of areasse3 flanges 35 and 36 by 0.161 inch. It should be understood that theforegoing and other dimensions set forth herein are given solely by wayof example and are not intended to limit the invention.

Round holes 51 and 52 may be provided adjacent each route for convenientattachment of main runner supporting wires, as is well known in the art.

As shown in FIGS. 4 and 5, the cross-Ts are also shaped with an invertedT cross section and have a vertical web 53 formed from vertical portions54 and 55 joined by a rounded rib 56 and terminating, respectively, inhorizontal ceiling panel supporting flanges 57 and 58 capped by adecorative flange cover 59.

The cross-T may have a central route 6% for attachment of a bridging T,as is well known. For convenience of illustration, the cross-T is brokenoff at 61 and 62, although the overall axial length thereof might be 2or 4 feet.- Generally, the cross-T height will be somewhat less than themain runner height, and the cross-T may be made of lighter gauge metal.

The two ends of the cross-T are identical and each comprises -a verticalshoulder 63 formed by the axial ends of the flanges 57 and 58 and by therear of a notch in the end of the cross-T web. The ends also comprise ahorizontal shoulder 64, an inclined shoulder 65, a horizontal shoulder66, a vertical shoulder 67, a horizontal shoulder 68, and a verticalshoulder 69, all formed in the web -3, and an inclined shoulder 70formed in rounded rib 56. An elongated open-topped slot 7-1 is formedadjacent each end of the cross-T by removal of that portion of roundedrib 56 between vertical shoulders 72 and 73.

Shoulders 72 and 73 might be located axially and 2 /2 .lower half of theweb adjacent each end of the cross-T and located axially outwardly ashort distance from the respective shoulders 73. A round hole 75 isprovided adjacent each end of the cross-T. The holes 75 are formed abouta center located above a respective shoulder 64 and axially inwardly ofa respective shoulder 67.

A hook latch, as illustrated in FIGS. 6, 7 and 8, is at- .tached to eachend of each cross-T for releasable locking attachment of the cross-Ts tothe main runners, The hook latch may be formed from a single sheet ofmetal and comprises a flat body portion 76 having a rivet-receiving hole77 near the forward edge thereof. The body portion 76 is adapted .to beconnected to a cross-T web by means of a rivet or other suit-ablefastener acting in hole 77 and in cross-T hole 75. This attachmentpermits the hook latch to be pivoted about the center line of therivet-receiving holes with the body portion 76 in sliding contact-withthe adjacent cross-T web surface 54 or 55.

. The hook latch body 76 has an inclined bottom surface 78 and aninclined upper surface 79. The surface 79 terminates at its forward endin a horizontal surface 80, which in turn terminates in a forwardlyprojecting nose 81 having a hook-latching surface formed by a shoulder82 projecting upwardly at a slight rearward incline, e.g., 11 withrespect to the vertical from surface 80. As best shown in FIG. 7, nose8% is displaced laterally slightlywith respect to body portion 76. Theupper end of shoulder 82 meets a horizontal surface 83, which in turnmeets an inclined surface 84. The inclined surface 84 joins a roundedsurface 85, which in turn meets an inclined surface 86 .to complete thenose 81.

The forward lower end of the hook latch is formed with sidewardlyextending legs 87 and 88 located on opposite sides of the body 7-6.Upper edge 89 of leg 87 is joined to surface86 by .a rounded surface 90in the forward edge of the body portion 76. The upper edge 91 of leg 88is inclined upwardly from side edge 92 thereof and joins leg 87 at anintermediate height. The bottom of leg 87 is formed by a horizontal footsurface 93 which meets a slightly concave surface 94 which extends into3 leg 88 and meets a horizontal foot surface 95 at the bottom side edgeof leg 88.

The lower rear edge of body portion 76 is provided with a sidewardlyextending lug 96 having an outer side edge Q7 inclined inwardly from thetop to the bottom of lug 96. The lug 96 extends sidewa-rds from bodyportion 76 in the same direction as leg 88.

The rear upper edge of body portion 76 is provided with a sidewardlyextending horizontal flange 98, The outer edge of flange 98 is providedwith a slot 99 from the center of which projects a downwardly andoutwardly extending finger 1%. A slot 101 may be provided in bodyportion 76 to facilitate forming of flange 98. The flange 98 extendssidewards from body portion 76 in the same direction as leg 88.

The hook latch of FIGS. 68 is intended to be installed on the left sideof the cross-T web, considering right and left as determined by lookingaxially along the cross- T from the center toward the end in question.The hook latches on both ends of each cross-T could .be identical.However, as will be explained below, added stability and rigidity areachieved by making the hook latch on one end of each cross-T a left-handhook latch, as in FIGS. 68, and making the hook latch on the other endof each cross- T a right-hand hook latch. By a right-hand hook latch ismeant a hook latch intended to be installed on the right side of thecross-T web. A right-hand hook latch is essentially a mirror image ofthe hook latch of FIGS. 6-8, i.e., those elements projecting to one sideof body portion 76 in left-hand hook latch of FIGS. 6-8

project on the opposite side in a right-hand hook latch.

By using a right-hand hook latch on one end of a cross-T and a left-handhook latch on the other end thereof, the hook latches are both installedon the same web surface, which might be either the surface 54- on thesurface 55 of the cross-T of FIGS. 4 and 5. Assuming a left-hand hooklatch to be installed on the left end of the cross-T in FIG. 4 and aright-hand hook latch to be installed on the right end thereof, bothhook latches would be installed against the surface 54 of web 53.

Referring to FIG. 1, the hook latches 23B, 2413, 25A, 26A, 27B, 28B, 29Aand 36A are left-hand, while hook latches 25B, 26B, 27A and 28A areright-hand. It will be evident from FIG. 1 that the hook latches onadjacent ends of two cross-Ts abutting corresponding points on oppositesides of a main runner should both be of either the right-hand orleft-hand type. Thus, after cross-T 25 is installed between main runners20 and 21 with its"right-hand hook latch engaging main runner 21,cross-T 27 should be installed with its righthand hook latch engagingmain runner 2.1. Since the cross-Ts will normally be shipped with allright-hand hook latches at the same end of the shipping box, this willinvolve turning one of the cross-Ts end for end before installation. i i

The assembled relationship of the hook latches to the cross-Ts and theassembled relationship of cross-Ts to the main runners are bestillustrated in FIGS. 9-ll. In these figures the hook'latches are shownas'the righthand type but the same reference numerals are used as inFIGS. 6-8. in FIGS. 9-1l the main runner is designated 102, while thecross-Ts are designated N3 and 104. The hook latches for cross-Ts 103and 164 are designated 165 and 166, respectively.

The cross-T 103 is shown fully attached to main runner 102 in FIGS. 10and 11. In this condition, the shoulder 63 formed by the ends of thecross-T flanges 57 and 58 abut against the adjacent outer edge of mainrunner flange 35; abutment actually will be against cap covering 37 ifthe latter is used. The bottom surfaces of the flanges are flush,providing the desired smooth ceiling surface. The lower edge of thecross-T for- Ward edge is in the form of a notch which permits shoulder64 to rest on the adjacent main runner flange.

The forwardly projecting nose of web 53 formed by shoulder 69 abutsagainst the adjacent surface of main runner web 31. Nose 81 of hooklatch 105 projects through the upper right-hand side of route 38 in mainrunner web 31, and the upper edge of shoulder 82 of nose 81 contacts theopposite surface of web 31 from that contacted by nose 69. The point ofcontact of shoulder 82 and web 31 is slightly above the top surface ofroute 38 but below nose 69. The shoulder 82 in contacting web 31 causesa squeezing or gripping action which produces a tight contactbetweenshoulder 82 and web 31, between nose 69 and web 31, betweenshoulder 64 and flange 35, and between shoulder 63 and flange 35. Thesetight contacts alford substantial stability and rigidity in a verticalplane. The contact between shoulder 63 and flange 35 also affordssubstantial stability of rigidity in a horizontal plane which isenhanced by contact of feet 93 and 95 of legs 87 and 88 with axiallyspaced areas on the upper surface of main runner flange 35. It will beobserved that legs 87 and 88 are parallel to main runner web 31 but arelaterally spaced therefrom. This lateral spacing aids in affording thestability and rigidity in a vertical plane.

Lug 96 of hook latch 105 projects into slot 74 in cross-T web 53, andcontact between the upper surface of lug 96 and the top surface of slot74 prevents the hook latch from pivoting about its rivet 107 in aclockwise direction (FIG. Lug 96 is prevented from leaving slot 74 bycontact between finger 100 and the adjacent surface of web 53. Thelateral spacing between the upper end of finger 100 and web 53 should besufficient to permit some lateral motion of lug 96 but not suflicientfor the lug 96 to accidentally lose contact with the upper surface ofslot 74.

Installation of the cross-T to the main runner may be effected as shownfor the cross-T 103 in FIG. 9 and for the cross-T 104 in FIG. 10. Thecross-T hook latch initially is in a pivoted position with the bottom oflug 96 resting on the bottom Wall of slot 71 in web 53. Pivoting of thehook latch substantially beyond this position is prevented by contactbetween leg 88 and shoulder 65. The cross-T is brought into closeproximity with the main runner with nose 81 of the hook latch insertedthrough the beam route 38. This insertion is through one side of thebeam route for cross-T 103 and through the other side for cross-T 104.In each case the hook latch will be inserted in the right half of thebeam route as viewed axially toward the main runner web. Nose 69 isbrought into contact with web 31 and feet 93 and 95 are brought intocontact with the adjacent main runner flange.

The rear of the cross-T hook latch is then sprung outwardly away fromthe cross-T web, as by exerting a lateral force on the finger 100. Sincethe edge 97 of lung 95 is inclined, the bottom edge of lug 96 is shorterthan the top surface. This shorter lug buttom edge facilitates outwardspringing of the hook latch. Gnce thebottom edge ofthe lug 96 is clearof the top edge of the cross-T web, the rear of the cross-T hook latchis pivoted downwardly, as by exerting a force on the top surface offlange 98. When the top edge of lug 96 clears the top surface of slot74, the lug 96 will spring inwardly into the slot 74, bringing the hooklatch into close contact with the cross-T web.

As the rear of the hook latch is being pivoted downwardly, the nose 81is being pivoted upwardly, bringing the shoulder 82 into tight contactwith the main runner web. It is desirable that substantial manual forcebe required to pivot completely the hook latch so that tight contactwith the main runner will be assured.

The leg 87 extends axially along the main runner flange away from theroute 38. However, the leg 87 extends past that portion of the route 38to be occupied by the opposite cross-T, e.g., the cross-T 104. Theheight of leg 88 is kept small so that the leg 88 will not obstruct theroute portion to be occupied by the opposite cross-T.

By offsetting hook latch nose 81 slightly to the side, as best shown inFIG. 7, a substantial axial separation may be made between the mainrunner web areas contacted by the noses 81 of opposing cross-T hooklatches, this separation being that provided by the surface 49 (FIG. 2).Nevertheless, nose ends 69 of opposing cross- Ts contact identical areason opposite sides of the main web.

As mentioned previously, it is desirable that the cross- T hook latchesat each end of a cross-T be on the same side of the cross-T. The reasonfor this is that with this arrangement the cross-T may be disposedexactly perpendicular to the main runners, affording a grid structure ofgreater rigidity than if the cross-Ts were disposed at a slight angleother than 90. Such angular disposition would be required if the hooklatch on one end of a cross- T were on the opposite side of the cross-Tweb from the hook latch at the other end.

Disassembly of the cross-T from the main runner may be effected byforcing the rear end of the cross-T hook latch outwardly of the cross-Tweb until the top edge of lug 96 clears the upper surface of slot 74.The rear end of the hook latch is then pivoted upwardly, freeing theshoulder 82 from the main runner web and at the same time freeingshoulder 69 from the main runner Web and shoulder 63 and feet 93 and 95from the main runner flange. In a fully installed grid system, a slightflexing of the main runner and/or cross-T would be needed to freecompletely the first end of the cross-T. To prevent accidentaldisengagement of lug 95 from slot 74, it is desirable that the forcerequired to efiect this disengagement be considerable and hencedisassembly may require the use of a screwdriver or like tool to forcethe lug 96 out of slot 74. However, provision of the inclined edge 97 onlug 96 permits assembly of the cross-T to the main runner without theuse of tools, since it is easier to urge the rear end of the hook latchoutwardly by exerting a downward force on flange 93 than to force therear end outwardly by lateral motion only. And during assembly the loweredge of the lug 96 will clear the web 53 without interference fromfinger 100, since the latter will initially be pivoted to a point abovethe web 43, as shown in FIG. 9.

While the invention has been described in connection with a specificembodiment thereof and in a specific use, various modifications thereofwill occur to those skilled in the art without departing from the spiritand scope of the invention as set forth in the appended claims.

What is claimed is:

1. In a suspended ceiling grid structure having a main runner andtransverse cross-T positioned parallel to each other .at opposite sidesof the main runner, said main runner having an axially extendingupstanding web and a pair of axially extending flanges projectinghorizontally from the main runner web, said main runner web having aplurality of axially spaced apertures located at an intermediate heightin said main runner web, the im provement comprising: said cross-Ts eachhaving an axially extending upstanding web and a pair of axiallyextending flanges projecting horizontally from the cross- T web butterminating axially inwardly of the forward end of the cross-T Web by adistance substantially equal to the width of a main runner flange, afirst shoulder forming the forward end of each cross-T web at the end ofthe latter facing said main runner and located so as to be in contactwith the adjacent main runner web above the top of one of said mainrunner apertures when the forward edge of the corresponding cross-Tflange is aligned with and in contact with the outside edge of theadjacent main runner flange, said cross-T webs each having a closedsided aperture located inwardly of each forward end thereof, and a pairof hook latching elements each attached to a respective cross-T webadjacent the forward end thereof, said attachment of said hook latchingelements of said cross-T webs permitting pivoting of said hook latchingelements in a substantially vertical plane between an unlatched positionand a latched position,

each hook latching element comprising a flat body portion disposed so asto be in slidable contact with one cross-T web surface, a locking lugprojecting laterally from said body portion and arranged to enter theadjacent cross-T Web aperture when said hook latching element is pivotedto said latched position thereof, a forwardly extending nose adapted toenter said one main runner, aperture when said cross-T is aligned withsaid one main runner aperture and having an upwardly extending secondshoulder arranged to contact the opposite surface of said main runnerweb above the top of said one main runner aperture when said hooklatching element is pivoted to said latched position thereof, a pair oflegs projecting laterally in opposite directions from said body portionand each having a foot surface arranged to contact the upper surface ofthe adjacent main runner flange and a flange extension projectinglaterally from said body portion and arranged to contact the oppositecross-T web surface when said hook latching element is pivoted to saidlatched position thereof thereby to prevent accidental disengagement ofsaid lug from said cross-T web aperture.

2. In a suspended ceiling grid structure having a main runner andtransverse cross-Ts positioned parallel to each other .at opposite sidesof the main runner, said main runner having an axially extendingupstanding web and a pair of axially extending flanges projectinghorizontally from the base of the main runner web, said main runner webhaving a plurality of axially spaced apertures located at anintermediate height in said main runner web, the improvement comprising:said cross-Ts each having an axially extending upstanding web and a pairof axially extending flanges projecting horizontally from the base ofthe cross-T web but terminating axially inwardly of the forward end ofthe cross-T web by a distance substan tially equal to the width of amain runner flange, a vertical shoulder forming the forward end of eachcross-T web at the end of the latter facing said main runner and locatedso as to be in contact with the adjacent main runner web above the topof one of said main runner apertures when the forward edge of thecorresponding cross-T flange is aligned with and in contact with theoutside edge of the adjacent main runner flange, said cross-T webs eachhaving a closed sided aperture located inwardly of each forward endthereof, and a pair of hook latching elements each attached to arespective cross-T web adjacent the for-ward end thereof, saidattachment of said hook latching elements to said cross-T webspermitting pivoting of said hook latching elements in a substantiallyvertical plane between an unlatched position and a latched position,each hook latching element comprising a flat body portion disposed so asto be in slidable contact with one cross-T web surface, a locking lugprojecting laterally from said body portion and arranged to enter theadjacent cross-T web aperture when said hook latching element is pivotedto said latch position thereof, a forwardly extending nose adapted toenter one side of said one main runneraperture when said cross-T isaligned with said one main runner aperture and having an upwardlyextending shoulder arranged to contact the opposite surface of said mainrunner web above the top of said one main runneraperture when said hooklatching element is pivoted to said latched position thereof, a pair oflegs projecting laterally in opposite directions from said bodyportionand each having a foot surface arranged to contact the upper surface ofthe adjacent main runner flange outwardly of the main runner Web and aflange extension projecting laterally from said body portion andarranged to surmount the cross-T web andcontact the opposite cross-T websurface when said hook latching element deliberate withdrawal of saidlug from said cross-T web aperture therebytto permit said hook latchingelement to be pivoted to said unlatched position thereof in which saidupwardly extending shoulder is free of the adjacent main runner websurface and said cross-T may be disengaged from said main runner.

3. The combination set forth in claim 2 in which the hook latchingelements attached to said forward ends of said cross-T webs aresubstantially mirror images of each other.

4. The combination set forth in claim 2 in which the hook latchingelement leg extending axially across the other side of said one mainrunner aperture has a top edge located below the bottom edge of saidother side of said one main runner aperture.

5. The combination set forth in claim 2 in which said lug has an outeredge inclined so that the upper edge of said lug is substantially longerthan the lower edge of said lug.

6. The combination set forth in claim 2 in which said upwardly extendingshoulder of said hook latching element nose is inclined to limit contactbetween said upwardly extending shoulder and said opposite surface ofsaid main runner web to an area adjacent the upper end of said upwardlyextending shoulder.

7. In a suspended ceiling grid structure having a main runner andtransverse cross-Ts positioned parallel to each other at opposite sidesof the main runner, said main runner having an axially extendingupstanding web and a pair of axially extending flanges projectinghorizontally from the base of the main runner web, said main runner webhaving a plurality of axially spaced apertures located at anintermediate height in said web, the improvement comprising: saidcross-Ts each having an axially extending upstanding web and a pair ofaxially extending flanges projecting horizontally from the base of thecross-T web but terminating axially inwardly of the forward end of thecross-T web by a distance substantially equal to the width of a mainrunner flange, a vertical shoulder forming the forward end of eachcross-T web at the end of the latter facing said main runner and locatedso as to be in contact with the adjacent main runner web above the topof one of said main runner apertures when the forward edge of thecorresponding cross-T flange is aligned with and in contact with theoutside edge of the adjacent main runner flange, said cross-T webs eachhaving a rectangular aperture located at an intermediate height andinwardly of the forward end thereof, the forward ends of said cross-Twebs each having a notch in the lower edge thereof forming a horizontalshoulder arranged to contact the upper surface of the adjacent mainrunner flange when the forward edge of said cross-T flange is alignedwith and in contact with the outside edge of said adjacent main runnerflange, and a pair of hook latching elements each attached to arespective cross'T Web adjacent the forward end thereof, said attachmentof said hook latching elements to said cross-T webs permitting pivotingof said hook latching elements in a substantially vertical plane betweenan unlatched position and a latched position, each hook latching elementcomprising a flat body portion disposed as to be in slidable contactwith the cross-T Web surface, a locking lug projecting laterally fromsaid body portion and arranged to enter the adjacent cross-T webaperture when said hook latching element is pivoted to said latchedposition thereof, said locking lug having a horizontal upper edge, ahorizontal lower edge shorter than said upper edge and an inclinedforward edge joining said upper and lower edges thereof, said lower edgeof said locking lug being arranged to rest on an upper edge of saidcross-T web when said hook latching element is in said unlatchedposition thereof, a forwardly extending nose adapted to enter one sideof said one main runner aperture when said cross-T is aligned with saidone main runner aperture and having an upwardly extending shoulderarranged to contact the opposite main runner web surface above the topof said one main runner aperture when said hook latching element ispivoted to said latched position thereof, said nose being offset in thedirection of said one side of said one main runner aperture, a pair oflegs projecting laterally in opposite directions from said body portionand each having a foot surface arranged to contact the upper surface ofthe adjacent main runner flange outwardly of the main runner web, and aflange extension projecting laterally from said body portion andarranged to surmount the cross-T web and contact the opposite cross-Tweb surface when said hook latching element is pivoted to said latchedposition thereof thereby to prevent accidental disengagement of said lugfrom said cross-T web aperture, said contact between said flangeextension and said opposite surface of said cross-T Web permittingdeliberate withdrawal of said lug from said cross-T web aperture therebyto permit said hook latching element to be pivoted to said unlatchedposition thereof in which said upwardly extending shoulder is free ofthe adjacent main runner web surface and said cross-T may be disengagedfrom said main runner.

8. In a suspended ceiling grid structure having a main runner andtransverse cross-Ts positioned parallel to each other at opposite sidesof the main runner, said main runner having an axially extendingupstanding web and a pair of axially extending flanges projectinghorizontally from the main runner web, said main runner web having anaperture located at an intermediate height in said web, the improvementcomprising: said cross-Ts each having an axially extending upstandingweb and a pair of axially extending flanges projecting horizontally fromthe cross-T web but terminating axially inwardly of the forward end ofthe cross-T web by a distance substantially equal to the width of a mainrunner flange, a nose surface forming the forward end of each cross-Tweb at the end of the latter facing said main runner and located so asto be in contact with the adjacent main runner web when the forward edgeof the corresponding cross-T flange is aligned with and in contact withthe outside edge of the adjacent main runner flange, said cross-T webseach having a closed sided aperture located inwardly of each forward endthereof, and a pair of hook latching elements each attached to arespective cross-T web adjacent the forward end thereof, said attachmentof said hook latching elements to said cross-T webs permitting pivotingof said hook latching elements in a substantially vertical plane betweenan unlatched position and a latched position, each hook latching elementcomprising a body portion disposed so as to be in contact with thecross-T web surface, a locking lug projecting laterally from said bodyportion and arranged to enter the adjacent cross-T web aperture whensaid hook latching element is pivoted to said latched position thereof,a forwardly extending nose adapted to enter said main runner aperturewhen said cross-T is aligned with said main runner aperture and havingan upwardly extending shoulder arranged to contact the opposite mainrunner web surface above the top of said main runner aperture when saidhook latching element is pivoted to said latched position thereof, and aleg projecting from said body portion and having a foot surface arrangedto contact an upper surface of a flange of the adjacent main runner.

References Cited by the Examiner UNITED STATES PATENTS RICHARD W. COOKE,JR., Primary Examiner.

6/63 Purdy .189--36

1. IN A SUSPENDED CEILING GRID STRUCTURE HAVING A MAIN RUNNER ANDTRANSVERSE CROSS-T POSITIONED PARALLEL TO EACH OTHER AT OPPOSITE SIDESOF THE MAIN RUNNER, SAID MAIN RUNNER HAVING AN AXIALLY EXTENDINGUPSTANDING WEB AND A PAIR OF AXIALLY EXTENDING FLANGES PROJECTINGHORIZONTALLY FROM THE MAIN RUNNER WEB, SAID MAIN RUNNER WEB HAVING APLURALITY OF AXIALLY SPACED APERTURES LOCATED AT AN INTERMEDIATE HEIGHTIN SAID MAIN RUNNER WEB, THE IMPROVEMENT COMPRISING: SAID CROSS-T''SEACH HAVING AN AXIALLY EXTENDING UPSTANDING WEB AND A PAIR OF AXIALLYEXTENDING FLANGES PROJECTING HORIZONTALLY FROM THE CROSST WEB BUTTERMINATING AXIALLY INWARDLY OF THE FORWARD END OF THE CROSS-T WEB BY ADISTANCE SUBSTANTIALLY EQUAL TO THE WIDTH OF A MAIN RUNNER AND LOCATEDSO AS TO FORMING THE FOWARD END OF EACH CROSS-T WEB AT THE END OF THELATTER FACING SAID MAIN RUNNER AND LOCATED SO AS TO BE IN CONTACT WITHTHE ADJACENT MAIN RUNNER WEB ABOVE THE TOP OF ONE OF SAID MAIN RUNNERAPERTURES WHEN THE FORWARD EDGE OF THE CORRESPONDING CROSS-T FLANGE ISALINGED WITH AND IN CONTACT WITH THE OUTSIDE EDGE OF THE ADJACENT MAINRUNNER FLANGE, SAID CROSS-T WEBS EACH HAVING A CLOSED SIDED APERTURELOCATED INWARDLY OF EACH FORWARD END THEREOF, AND A PAIR OF HOOKLATCHING ELEMENTS EACH ATTACHED TO A RESPECTIVE CROSS-T WEB ADJACENT THEFORWARD END THEREOF, SAID ATTACHMENT OF SAID HOOK LATCHING ELEMENTS OFSAID CROSS-T WEBS PERMITTING PIVOTING OF SAID HOOK LATCHING ELEMENTS INA SUBSTANTIALLY VERTICAL PLANE BETWEEN AN UNLATCHED POSITION AND ALATCHED POSITION, EACH HOOK LATCHING ELEMENT COMPRISING A FLAT BODYPORTION DISPOSED SO AS TO BE IN SLIDABLE CONTACT WITH ONE CROSS-T WEBAPERTURE WHEN SAID HOOK LATCHING ELEMENT FROM SAID BODY PORTION ANDARRANGED TO ENTER THE ADJACENT CROSS-T WEB APERTURE WHEN SAID HOOKLATCHING ELEMENT IS PIVOTED TO SAID LATCHED POSITION THEREOF, AFORWARDLY EXTENDING NOSE ADAPTED TO ENTER SAID ONE MAIN RUNNER APERTUREWHEN SAID CROSS-T IS ALIGNED WITH SAID ONE MAIN RUNNER APERTURE ANDHAVING AN UPWARDLY EXTENDING SECOND SHOULDER ARRANGED TO CONTACT THEOPPOSITE SURFACE OF SAID MAIN RUNNER WEB ABOVE THE TOP OF SAID ONE MAINRUNNER APERTURE WHEN SAID HOOK LATCHING ELEMENT IS PIVOTED TO SAIDLATCHED POSITION THEREOF, A PAIR OF LEGS PROJECTING LATERALLY INOPPOSITE DIRECTIONS FROM SAID BODY PORTION AND EACH HAVING A FOOTSURFACE ARRANGED TO CONTACT THE UPPER SURFACE OF THE ADJACENT MAINRUNNER FLANGE AND A FLANGE EXTENSION PROJECTING LATERALLY FROM SAID BODYPORTION AND ARRANGED TO CONTACT THE OPPOSITE CROSS-T WEB SURFACE WHENSAID HOOK LATCHING ELEMENT IS PIVOTED TO SAID LATCHED POSITION THEREOFTHEREBY TO PREVENT ACCIDENTAL DISENGAGEMENT OF SAID LUG FROM SAIDCROSS-T WEB APERTURE.